The present invention is concerned with an improvement in the lathering and wear rate properties of a toilet detergent bar having an acyl isethionate as the predominate surface-active detergent and an unesterified water-soluble alkali metal isethionate as a bar processing aid.
One of the problems of acyl isethionate toilet detergent bars is their unusually high wear rate despite the attention given to other properties of this type of bar. For example, in U.S. Pat. No. 4,007,125, incorporated herein by reference, it was found that the mush properties of an acyl isethionate detergent bar could be improved by adding to the bar an amount of sodium alkane sulfonate wherein the alkane group has 12 to 14 carbon atoms. And in application Ser. No. 428,287, filed Dec. 26, 1973, now abandoned, the mush properties of the same kind of bar are improved by the addition of a mixture of sodium sulfate and sodium chloride. However, regardless of the improvement in the mush properties obtained with the detergent bars according to these applications, the wear rate of these bars still remains a problem, and any attempt to improve this latter property has heretofore been accomplished at the expense of lathering.
The use of alkoxy hydroxy propane sulfonates in soap bars has been described in U.S. Pat. No. 2,987,484 issued on June 6, 1961, wherein sodium and potassium alkyl glyceryl ether sulfonates have been incorporated in soap bars as anionic surface active agents in amounts of 35% and above. And in U.S. Pat. No. 2,988,511, issued on June 13, 1961, alkyl glyceryl ether sulfonates are described as major anionic detergent actives, which can be used in combination with the isethionates. The lathering boosting properties of alkyl glyceryl ether sulfonate compounds, however, when used in relatively small amounts with acyl isethionates as the major surfactant have not been recognized.